KR20200068706A - Display module with quasi-static and dynamic impact resistance - Google Patents

Abstract

The display module includes: a glass-containing cover element having a thickness of about 25 μm to about 200 μm, an elastic modulus of about 20 to 140 GPa, and first and second major surfaces; And a stack, the stack comprising: (a) a substrate comprising a component having a thickness of about 100 μm to 1500 μm and a glass composition, and (b) connecting the stack to a second major surface of the cover element. And a first adhesive comprising an elastic modulus of about 0.001 GPa to about 10 GPa and a thickness of about 5 μm to 50 μm. Moreover, the display module includes impact resistance characterized by a tensile stress of less than about 3700 MPa at the second major surface of the cover element upon impact to the cover element in a semi-static indentation test.

Description

Display module with quasi-static and dynamic impact resistance

This application claims the priority of U.S. Provisional Application No. 62/571,017, filed on October 11, 2017, the contents of which are incorporated herein by reference in their entirety.

The present disclosure relates generally to display modules and articles that are bendable, and more particularly to bendable display modules that include a glass-containing cover.

In fact, flexible versions of traditionally robust products and components are being conceptualized for new applications. For example, a flexible electronic device can provide thin, lightweight and flexible properties that provide opportunities for new applications, including curved displays and wearable devices. Many of these flexible electronic devices include flexible substrates for holding and mounting electronic components of these devices. Metal foils have several advantages, including thermal stability and chemical resistance, but suffer from high cost and lack of optical transparency. Polymer foils have several advantages, including low cost and impact resistance, but suffer from marginal optical transparency, lack of thermal stability, limited tightness and cyclic fatigue performance.

Some of these electronic devices can also make use of flexible displays. Optical transparency and thermal stability are often desirable properties for flexible display applications. Additionally, flexible displays should have high fatigue and puncture resistance, including resistance to breakage at small bending radii, particularly for flexible displays that have touch screen functionality and/or can be folded. Moreover, the flexible display should be able to be easily bent and folded by the consumer, depending on the intended application for the display.

Some flexible glass and glass-containing materials provide many desirable properties for flexible and foldable substrate and display applications. However, efforts to use glass materials for these applications have been difficult to date. In general, glass substrates can be fabricated at very low thickness levels (<25 μm) to achieve increasingly smaller bending radii. These “thin” glass substrates suffer from limited puncture resistance. At the same time, thicker glass substrates (>150 μm) can be made with better puncture resistance, but these substrates lack adequate fatigue resistance and mechanical reliability when bending.

Moreover, such flexible glass materials can be used for electronic components (eg, thin film transistors (“TFT”), touch sensors, etc.), additional layers (eg, polymer electronic device panels) and adhesives (eg, As used as cover elements in modules that also include epoxy, optically clear adhesives (“OCAs”), the interaction between these various components and elements can result in a final product, eg, electronic It may lead to increasingly complex stress states present during use of the module in the display device. This complex stress state can lead to increased stress levels and/or stress concentration factors experienced by the cover element. As such, these cover elements may be vulnerable to cohesive and/or delamination failure modes in the module. Moreover, this complex interaction can lead to increased bending forces for the consumer to bend and fold the cover element.

Accordingly, there is a need for flexible, glass-containing material and module design using these materials for use in a variety of electronic device applications, particularly flexible electronic display device applications, particularly more, foldable display device applications. .

According to a first aspect of the present disclosure, a display module is provided, the display module having a thickness of about 25 μm to about 200 μm and a cover element modulus of about 20 GPa to about 140 GPa, glass composition, first major A cover element further comprising a surface, and a component having a second major surface; And a stack, the stack comprising: (a) a substrate comprising a component having a thickness and a glass composition of about 100 μm to 1500 μm, and (b) connecting the stack to a second major surface of the cover element. And a first adhesive comprising an elastic modulus of about 0.001 GPa to about 10 GPa and a thickness of about 5 μm to 50 μm. Moreover, the display module includes impact resistance characterized by a tensile stress of less than about 4700 MPa at the second major surface of the cover element upon impact to the cover element in a quasi-static indentation test. .

According to a second aspect of the present disclosure, a display module is provided, the display module having a thickness of about 25 μm to about 200 μm and a cover element elastic modulus of about 20 GPa to about 140 GPa, glass composition, first major A cover element further comprising a surface, and a component having a second major surface; And a stack, the stack comprising: (a) a substrate comprising a component having a thickness and a glass composition of about 100 μm to 1500 μm, and (b) connecting the stack to a second major surface of the cover element. And a first adhesive comprising an elastic modulus of about 0.001 GPa to about 10 GPa and a thickness of about 5 μm to 50 μm. Moreover, the display module has a tensile stress of less than about 4000 MPa at the first major surface of the cover element and about 12000 at the second major surface of the cover element upon impact to the cover element in the Pen-Drop Test. Impact resistance characterized by tensile stress less than MPa.

According to a third aspect of the present disclosure, a display module is provided, the display module having a thickness of about 25 μm to about 200 μm and a cover element elastic modulus of about 20 GPa to about 140 GPa, glass composition, first major A cover element further comprising a surface, and a component having a second major surface; And a stack; The stack comprises: (a) a substrate comprising a component having a thickness of about 100 μm to 1500 μm and a glass composition, and (b) connecting the stack to a second major surface of the cover element, and from about 0.001 GPa to A first adhesive comprising an elastic modulus of about 10 GPa and a thickness of about 5 μm to 50 μm. The display module includes impact resistance characterized by a tensile stress of less than about 4700 MPa at the second major surface of the cover element upon impact to the cover element in a quasi-static indentation test. Moreover, the display module, as measured during the semi-static indentation test, contains a stiffness of about 750 N/mm or greater.

Additional features and advantages will be described in the detailed description that follows, and in part is apparent to those skilled in the art from the detailed description below, or to the specific examples described herein, including the following detailed description, claims, as well as the accompanying drawings. It will be easily recognized by implementation. For example, various features can be combined according to the following specific examples.

Specific Example 1. Display module:

A cover element having a thickness of about 25 μm to about 200 μm and a cover element elastic modulus of about 20 GPa to about 140 GPa, further comprising components having a glass composition, a first major surface, and a second major surface; And a stack,

The stack is:

(a) a substrate comprising a component having a thickness of about 100 μm to 1500 μm and a glass composition, and

(b) connecting the stack to a second major surface of the cover element, the first adhesive comprising a modulus of elasticity of about 0.001 GPa to about 10 GPa and a thickness of about 5 μm to 50 μm,

Here, the display module includes impact resistance characterized by a tensile stress of less than about 4700 MPa at the second major surface of the cover element upon impact to the cover element in a quasi-static indentation test.

Embodiment 2. In the display module according to embodiment 1, the display module is characterized by a tensile stress of less than about 3200 MPa at the second major surface of the cover element upon impact to the cover element in a semi-static indentation test. Includes impact properties.

Embodiment 3. In the display module according to embodiment 2 or embodiment 3, the first adhesive further comprises a thickness of about 5 μm to about 25 μm, and the cover element has a thickness of about 50 μm to about 150 μm. Including more.

Embodiment 4 In the display module according to any one of Embodiments 1-3, the first adhesive is epoxy, urethane, acrylate, acrylic, styrene copolymer, polyisobutylene, polyvinyl butyral, ethylene vinyl acetate , Sodium silicate, optically clear adhesive (OCA), pressure sensitive adhesive (PSA), polymer foam, natural resin, or synthetic resin.

Embodiment 5 In the display module according to any one of Embodiments 1-4, the stack comprises:

(c) an intermediate layer having a thickness of about 25 μm to about 200 μm and an interlayer elastic modulus of about 20 GPa to about 140 GPa, further comprising components having a glass composition; And

(d) connecting the intermediate layer to a substrate, and further comprising a second adhesive comprising an elastic modulus of about 0.001 GPa to about 10 GPa and a thickness of about 5 μm to about 50 μm.

Embodiment 6 In the display module according to embodiment 5, the display module is characterized by a tensile stress of less than about 4200 MPa at the second major surface of the cover element upon impact to the cover element in a semi-static indentation test. Includes impact properties.

Embodiment 7. In the display module according to embodiment 6, each of the first and second adhesives further comprises a thickness of about 5 μm to about 25 μm, and each of the cover element and the intermediate layer is about 75 μm to about It further includes a thickness of 150 μm.

Embodiment 8. In the display module according to any one of embodiments 5-7, each of the first and second adhesives is an epoxy, urethane, acrylate, acrylic, styrene copolymer, polyisobutylene, polyvinyl butyral , Ethylene vinyl acetate, sodium silicate, optically clear adhesive (OCA), pressure sensitive adhesive (PSA), polymer foam, natural resin, or synthetic resin.

Specific Example 9. Display module:

A cover element having a thickness of about 25 μm to about 200 μm and a cover element elastic modulus of about 20 GPa to about 140 GPa, further comprising components having a glass composition, a first major surface, and a second major surface; And a stack,

The stack is:

(a) a substrate comprising a component having a thickness of about 100 μm to 1500 μm and a glass composition, and

(b) connecting the stack to a second major surface of the cover element, the first adhesive comprising a modulus of elasticity of about 0.001 GPa to about 10 GPa and a thickness of about 5 μm to 50 μm,

Here, the display module, in the pen drop test, a tensile stress of less than about 4000 MPa on the first major surface of the cover element and a tensile stress of less than about 11000 MPa on the second major surface of the cover element upon impact to the cover element in the pen drop test. It includes impact resistance characterized by.

Embodiment 10. In the display module according to embodiment 9, the display module comprises a tensile stress of less than about 4000 MPa on the first major surface of the cover element upon impact on the cover element in a pen drop test and a preparation of the cover element. 2 Includes impact resistance characterized by tensile stress of less than about 9000 MPa at the main surface.

Embodiment 11. In the display module according to embodiment 10, the first adhesive further comprises a thickness of about 5 μm to about 25 μm, and the cover element further comprises a thickness of about 50 μm to about 150 μm. .

Embodiment 12. In the display module according to any one of embodiments 9-11, the first adhesive is epoxy, urethane, acrylate, acrylic, styrene copolymer, polyisobutylene, polyvinyl butyral, ethylene vinyl acetate , Sodium silicate, optically clear adhesive (OCA), pressure sensitive adhesive (PSA), polymer foam, natural resin, or synthetic resin.

Embodiment 13. In the display module according to any of embodiments 9-12, the stack comprises:

(c) an intermediate layer having a thickness of about 25 μm to about 200 μm and an interlayer elastic modulus of about 20 GPa to about 140 GPa, further comprising components having a glass composition; And

(d) connecting the intermediate layer to a substrate, and further comprising a second adhesive comprising an elastic modulus of about 0.001 GPa to about 10 GPa and a thickness of about 5 μm to about 50 μm.

Embodiment 14. In the display module according to embodiment 13, the display module comprises a tensile stress of less than about 4000 MPa on the first major surface of the cover element upon impact on the cover element in a pen drop test and a preparation of the cover element. 2 Includes impact resistance characterized by tensile stress of less than about 11000 MPa at the main surface.

Embodiment 15. In the display module according to embodiment 14, each of the first and second adhesives further comprises a thickness of about 5 μm to about 25 μm, and each of the cover element and the intermediate layer is about 50 μm to It further comprises a thickness of about 150 μm.

Embodiment 16. In the display module according to any one of embodiments 13-15, each of the first and second adhesives is an epoxy, urethane, acrylate, acrylic, styrene copolymer, polyisobutylene, polyvinyl butyral, Ethylene vinyl acetate, sodium silicate, optically clear adhesive (OCA), pressure sensitive adhesive (PSA), polymeric foam, natural resin, or synthetic resin.

Embodiment 17. The display module is:

A cover element having a thickness of about 25 μm to about 200 μm and a cover element elastic modulus of about 20 GPa to about 140 GPa, further comprising components having a glass composition, a first major surface, and a second major surface; And a stack,

The stack is:

(a) a substrate comprising a component having a thickness of about 100 μm to 1500 μm and a glass composition, and

(b) connecting the stack to a second major surface of the cover element, the first adhesive comprising a modulus of elasticity of about 0.001 GPa to about 10 GPa and a thickness of about 5 μm to 50 μm,

Here, the display module includes impact resistance characterized by a tensile stress of less than about 4700 MPa at the second major surface of the cover element upon impact to the cover element in a quasi-static indentation test,

The display module was measured during a quasi-static indentation test and includes a stiffness of at least about 750 N/mm.

Embodiment 18. In the display module according to embodiment 17, the display module is characterized by a tensile stress of less than about 3200 MPa at the second major surface of the cover element upon impact to the cover element in a semi-static indentation test. It includes impact resistance, and the display module is measured during a quasi-static indentation test and includes a stiffness of about 1000 N/mm or more.

Embodiment 19. In the display module according to embodiment 18, the first adhesive further comprises a thickness of about 5 μm to about 25 μm, and the cover element further comprises a thickness of about 50 μm to about 150 μm. do.

Embodiment 20. In the display module according to embodiment 19, the first adhesive is epoxy, urethane, acrylate, acrylic, styrene copolymer, polyisobutylene, polyvinyl butyral, ethylene vinyl acetate, sodium silicate, optical Transparent adhesive (OCA), pressure sensitive adhesive (PSA), polymer foam, natural resin, or synthetic resin.

Specific Example 21. The display module is:

A cover element having a thickness of about 25 μm to about 200 μm and a cover element elastic modulus of about 20 GPa to about 140 GPa, further comprising components having a glass composition, a first major surface, and a second major surface; And a stack,

The stack is:

(a) a substrate comprising a thickness of about 100 μm to 1500 μm, and

(b) connecting the stack to a second major surface of the cover element, the first adhesive comprising a modulus of about 0.001 GPa to about 10 GPa and a thickness of about 5 μm to 50 μm, and wherein the display module is :

Impact resistance characterized by a tensile stress of less than about 4700 MPa at the second major surface of the cover element upon impact to the cover element in a semi-static indentation test;

Impact resistance characterized by a tensile stress of less than about 4000 MPa on the first major surface of the cover element and a tensile stress of less than about 12000 MPa on the second major surface of the cover element upon impact to the cover element in a pen drop test; And

Stiffness of at least about 750 N/mm as measured during the semi-static indentation test; It further includes at least one of.

It is understood that both the foregoing background art and the following detailed description are exemplary only and are intended to provide an overview or framework for understanding the nature and features of the claims. The accompanying drawings are included to provide further understanding, are incorporated herein, and constitute a part of this specification. The drawings serve to illustrate one or more embodiments, and to explain the principles and operation of various embodiments with detailed description. Directional terms as used herein-for example, top, bottom, right, left, front, back, top, bottom-are only made with reference to the drawings as shown and are not intended to mean absolute directions. Does not.

1A is a cross-sectional view of a three-layer display module in accordance with some aspects of the present disclosure.
1B is a cross-sectional view of a 5-layer display module in accordance with some aspects of the present disclosure.
2 shows a display module in a pen drop test device for measuring quasi-static and dynamic impact resistance, in accordance with some aspects of the present disclosure.
3A is a plot of the load applied to a module in a semi-static indentation test modeled to a maximum principal stress versus a load of 60 N at the second major surface of the cover element of the display module, according to some aspects of the present disclosure. (plot).
3B is a plot of strain versus load for a display module subjected to a quasi-static indentation test modeled to a peak load of 60N, according to some aspects of the present disclosure.
FIG. 4 is a plot of the maximum failure load for a portion of the module tested in the quasi-static indentation test and schematically shown in FIG. 3A.
5A is a plot of the maximum principal stress at the second major surface of the cover element of the display module versus the distance from the impact location, as modeled in the pen drop test with a pen drop height of 25 cm, according to some aspects of the present disclosure. .
5B is a plot of the maximum principal stress at the first major surface of the cover element of the display module versus the distance from the impact position, as modeled in the pen drop test with a pen drop height of 25 cm, according to some aspects of the present disclosure. to be.
6A and 6B show the maximum principal stress and strain at the second major surface of the cover element of the display module versus time versus impact, as modeled in the pen drop test with a pen drop height of 25 cm, according to some aspects of the present disclosure. Each plot.
FIG. 7 is a bar chart of maximum principal stress at the second principal surface of the cover element of the display module shown in FIGS. 3A-6B, with the percentage increase in each stress value relative to the lowest maximum principal stress observed in the sample.

In the following, reference will be made in detail to specific examples according to the claims, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numerals refer to the same or similar parts and will be used throughout the drawings. Ranges can be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another embodiment includes from one specific value and/or to another specific value. Similarly, by the use of the predecessor “about,” it will be understood that when values are expressed as approximations, certain values form another embodiment. Regardless of whether a numerical value or end-point of a range is referred to herein as “about”, a numerical value or end-point of a range is one modified by two embodiments: “about” and “about” It is intended to include the other, which is not changed by ". It will be further understood that the endpoints of each range are meaningful, in relation to and other endpoints.

The terms “substantial”, “substantially” and variations thereof are intended to indicate that the described features are the same or nearly identical to the values or descriptions. For example, a “substantially planar” surface is intended to represent a planar or nearly planar surface. Moreover, "substantially" is intended to indicate that the two values are the same or nearly identical. In some embodiments, “substantially” can represent values within about 10% of each other, such as within about 5% of each other, or within about 2% of each other.

Among other features and advantages, the display modules and articles of the present disclosure provide unexpectedly high quasi-static and dynamic impact resistance. These modules achieve this level of impact through the design of the thickness of the adhesive and cover elements, along with the number of layers in the module. Moreover, the improvement of the impact resistance properties associated with these modules can also contribute to mechanical reliability and puncture resistance. With regard to mechanical reliability, the display modules of the present disclosure are configured to avoid damage to their glass-containing cover elements upon flexing, bending or other deformations to the modules. For example, the display module may include a cover on the user-facing portion of the foldable electronic display device, a position where puncture resistance is particularly desirable; A substrate module disposed inside the device itself and having electronic components disposed thereon; Or it can be used as one or more of any other place in the display device. Optionally, the display module of the present disclosure does not have a display, but a glass or glass-containing layer is used for its beneficial properties, and with a tight bending radius, in a similar manner as in a foldable display, the device is folded or bent. Can be used. Perforation resistance is particularly advantageous when the display module is used outside of the device, at a location where the user will interact.

More specifically, display modules and articles of the present disclosure may obtain some or all of the above-mentioned advantages through control of the material properties and thickness of the cover elements, adhesives and interlayers used in the modules. For example, such a display module can be measured in a modeled or actual semi-static indentation or dynamic pen drop test, through increased thickness of the intermediate layer, increased elasticity of the intermediate layer and/or increased elasticity of the first adhesive. It can exhibit improved impact resistance, characterized by reduced tensile stress at the major surface of the element. These low tensile stresses associated with quasi-static and dynamic loads can lead to improved module reliability in terms of damage resistance of the cover element, especially as the modules undergo application-driven impact evolutions. have. In addition, embodiments and concepts of the present disclosure provide the skilled worker with a framework for designing a display module to reduce tensile stress at the major surface of the cover element, which is a different degree and amount of bending and folding evolution. evolutions) can contribute to the reliability, manufacturability and suitability of these modules for use in a variety of applications.

Referring to FIG. 1A, the display module 100a is shown in a representative form as a three-layer module, according to some aspects of the present disclosure. The module 100a includes a cover element 50, a first adhesive 10a, and a substrate 60. Moreover, the referenced stack 90a includes an adhesive 10a and a substrate 60. Moreover, the cover element 50 has a thickness 52, a first major surface 54 and a second major surface 56. The thickness 52 is about 25 μm to about 200 μm, for example about 25 μm to about 175 μm, about 25 μm to about 150 μm, about 25 μm to about 125 μm, about 25 μm to about 100 μm, About 25 μm to about 75 μm, about 25 μm to about 50 μm, about 50 μm to about 175 μm, about 50 μm to about 150 μm, about 50 μm to about 125 μm, about 50 μm to about 100 μm, about 50 Μm to about 75 μm, about 75 μm to about 175 μm, about 75 μm to about 150 μm, about 75 μm to about 125 μm, about 75 μm to about 100 μm, about 100 μm to about 175 μm, about 100 μm to About 150 μm, about 100 μm to about 125 μm, about 125 μm to about 175 μm, about 125 μm to about 150 μm, and about 150 μm to about 175 μm. In other aspects, the thickness 52 can range from about 25 μm to 150 μm, from about 50 μm to 100 μm, or from about 60 μm to 80 μm. The thickness 52 of the cover element 50 can also be set to a different thickness or thickness range between the aforementioned ranges. Some aspects of the display module 100a, compared to the thickness of other glass cover elements used in such electronic device applications, cover elements 50 of a relatively thin thickness, for example from about 75 μm to about 125 μm. It includes. The use of these cover elements 50 with relatively thinner thickness values was observed in the first and second major surfaces 54, 56 of the cover elements 50 upon impact in a semi-static indentation or pen drop test. As shown in reduced tensile stress, it provides improved resistance to unexpected quasi-static and dynamic impacts.

The display module 100a shown in FIG. 1A may be about 20 GPa to about 140 GPa, for example, about 20 GPa to about 120 GPa, about 20 GPa to about 100 GPa, about 20 GPa to about 80 GPa, about 20 GPa to about 60 GPa, about 20 GPa to about 40 GPa, about 40 GPa to about 120 GPa, about 40 GPa to about 100 GPa, about 40 GPa to about 80 GPa, about 40 GPa to about 60 GPa, about 60 GPa to Having a cover element modulus of about 120 GPa, about 60 GPa to about 100 GPa, about 60 GPa to about 80 GPa, about 80 GPa to about 120 GPa, about 80 GPa to about 100 GPa, and about 100 GPa to about 120 GPa It includes a cover element 50. The cover element 50 can be a component having a glass composition or can include at least one component having a glass composition. In the latter case, the cover element 50 can include one or more layers comprising a glass-containing material, for example, the cover element 50 is a second phase glass particles in a polymer matrix. It may be a polymer / glass composite consisting of). In some aspects, cover element 50 is a glass element characterized by an elastic modulus of about 50 GPa to about 100 GPa, or any modulus value or range of values between these limits. In other aspects, the cover element modulus is about 20 GPa, 30 GPa, 40 GPa, 50 GPa, 60 GPa, 70 GPa, 80 GPa, 90 GPa, 100 GPa, 110 GPa, 120 GPa, 130 GPa, 140 GPa, Or any modulus value or range of values between these values.

In particular aspects of the display module 100a shown in FIG. 1A, the cover element 50 can include a glass layer. In other aspects, the cover element 50 can include two or more glass layers. Thereby, the thickness 52 reflects the sum of the thicknesses of the individual glass layers that make up the cover element 50. From the viewpoint that the cover element 50 includes two or more individual glass layers, the thickness of each of the individual glass layers is 1 µm or more. For example, the cover element 50 used in module 100a can include three glass layers, each having a thickness of about 8 μm, so that the thickness 52 of cover element 50 is about 24 Μm. However, it should also be understood that the cover element 50 may include other non-glass layers (eg, compliant polymer layers) interposed between multiple glass layers. In another implementation of module 100a, cover element 50 may include one or more layers comprising a glass-containing material, for example, cover element 50 may include second phase glass particles in a polymer matrix. It may be a polymer / glass composite consisting of.

In FIG. 1A, a display module 100a comprising a cover element 50 comprising a glass material can be made from alkali-free aluminosilicates, borosilicates, boroaluminosilicates, and silicate glass compositions. Cover element 50 can also be made from alkali-containing aluminosilicates, borosilicates, boroaluminosilicates, and silicate glass compositions. In certain aspects, alkaline earth modifiers can be added to any of the aforementioned compositions for cover element 50. In some respects, the glass composition according to the following is suitable for a cover element 50 having at least one glass layer: 50 to 75% (mol%) SiO ₂ ; 5 to 20% Al ₂ O ₃ ; 8 to 23% B ₂ O ₃ ; 0.5 to 9% MgO; CaO from 1 to 9%; 0-5% SrO; 0-5% BaO; 0.1 to 0.4% Sn0 ₂ ; O to 0.1% Zr0 ₂ ; And 0 to 10% Na ₂ 0, 0 to 5% K ₂ 0, and 0 to 10% Li ₂ O. In some aspects, a glass composition according to a cover element having one or more glass layers ( 50): 64 to 69% (mol%) SiO ₂ ; 5 to 12% Al ₂ O ₃ ; 8 to 23% B ₂ O ₃ ; 0.5 to 2.5% MgO; CaO from 1 to 9%; 0-5% SrO; 0-5% BaO; 0.1 to 0.4% Sn0 ₂ ; 0 to 0.1% Zr0 ₂ ; And 0 to 1% Na ₂ 0. In other respects, the following composition is suitable for cover element 50: ~67.4% (mol%) SiO ₂ ; ˜12.7% Al ₂ O ₃ ; ˜3.7% B ₂ O ₃ ; ˜2.4% MgO; 0% CaO; 0% SrO; -0.1% Sn0 ₂ ; And ~13.7% Na ₂ 0. In further aspects, the following composition is also suitable for the glass layer used in the cover element 50: 68.9% (mol%) SiO ₂ ; 10.3% Al ₂ O ₃ ; 15.2% Na ₂ 0; 5.4% MgO; And 0.2% Sn0 ₂ . In other respects, the cover element 50 can use the following glass composition (“Glass 1”): ~65% (mol%) SiO ₂ ; ˜5% B ₂ O ₃ ; ~ 14% Al ₂ O ₃ ; ˜14% Na ₂ 0; And ~2 mol% MgO. In still other aspects, the following composition is also suitable for the glass layer used in the cover element 50: 68.9% (mol%) SiO ₂ ; 10.3% Al ₂ O ₃ ; 15.2% Na ₂ 0; 5.4% MgO; And 0.2% Sn0 ₂ . Ease of manufacture at low thickness levels while minimizing the incorporation of defects; Ease of occurrence of a compressive stress region to compensate for tensile stress generated during bending; Optical transparency; And a variety of criteria can be used to select a composition for a cover element 50 comprising a glass material, including, but not limited to, corrosion resistance.

The cover element 50 used in the foldable module 100a can adopt various physical shapes and shapes. From a single-sided perspective view, as a single layer or multiple layers, element 50 may be flat or planar. In some respects, element 50 may be manufactured in a non-rectangular, sheet-shaped form depending on the final application. By way of example, a mobile display device having an oval display and a bezel may use a cover element 50 having a generally oval, sheet-shaped shape.

Referring again to FIG. 1A, the display module 100a includes: a stack 90a having a thickness 92a of about 100 μm to 1600 μm; And a first adhesive 10a configured to connect the stack 90a to the second major surface 56 of the cover element 50, wherein the first adhesive 10a comprises a thickness 12a and about 0.001 GPa to about 10 GPa, for example, about 0.001 GPa to about 8 GPa, about 0.001 GPa to about 6 GPa, about 0.001 GPa to about 4 GPa, about 0.001 GPa to about 2 GPa, about 0.001 GPa to about 1 GPa , About 0.01 GPa to about 8 GPa, about 0.01 GPa to about 6 GPa, about 0.01 GPa to about 4 GPa, about 0.01 GPa to about 2 GPa, about 0.1 GPa to about 8 GPa, about 0.1 GPa to about 6 GPa, about It is characterized by an elastic modulus of 0.1 GPa to about 4 GPa, about 0.2 GPa to about 8 GPa, about 0.2 GPa to about 6 GPa, and about 0.5 GPa to about 8 GPa about 10 GPa. According to some implementations of the first aspect of the display module 100a, the first adhesive 10a is about 0.001 GPa, 0.002 GPa, 0.003 GPa, 0.004 GPa, 0.005 GPa, 0.006 GPa, 0.007 GPa, 0.008 GPa, 0.009 GPa , 0.01 GPa, 0.02 GPa, 0.03 GPa, 0.04 GPa, 0.05 GPa, 0.1 GPa, 0.2 GPa, 0.3 GPa, 0.4 GPa, 0.5 GPa, 0.6 GPa, 0.7 GPa, 0.8 GPa, 0.9 GPa, 1 GPa, 2 GPa, 3 It is characterized by an elastic modulus of any amount or range of amounts between GPa, 4 GPa, 5 GPa, 6 GPa, 7 GPa, 8 GPa, 9 GPa, 10 GPa, or these modulus values.

Referring back to the display module 100a shown in FIG. 1A, the first adhesive 10a is about 5 μm to about 60 μm, for example, about 5 μm to about 50 μm, about 5 μm to about 40 μm , About 5 μm to about 30 μm, about 5 μm to about 20 μm, about 5 μm to about 15 μm, about 5 μm to about 10 μm, about 10 μm to about 60 μm, about 15 μm to about 60 μm, about 20 μm to about 60 μm, about 30 μm to about 60 μm, about 40 μm to about 60 μm, about 50 μm to about 60 μm, about 55 μm to about 60 μm, about 10 μm to about 50 μm, about 10 μm To about 40 μm, about 10 μm to about 30 μm, about 10 μm to about 20 μm, about 10 μm to about 15 μm, about 20 μm to about 50 μm, about 30 μm to about 50 μm, about 40 μm to about It is characterized by a thickness 12a of 50 μm, about 20 μm to about 40 μm, and about 20 μm to about 30 μm. Other embodiments are about 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, or any of these thickness values. It has a first adhesive (10a) characterized by a thickness (12a) of a thickness or a range of thicknesses. In some aspects, the thickness 12a of the first adhesive 10a is between about 5 μm and 50 μm. Some aspects of the display module 100a provide a relatively thinner thickness, for example, an adhesive 10a of about 5 μm to about 25 μm, compared to the thickness of a conventional adhesive used in such electronic device applications. Includes. The use of this adhesive 10a with relatively thinner thickness values reduces the observed observed on the first and second major surfaces 54, 56 of the cover element 50 upon impact in a semi-static indentation or pen drop test. As shown in the tensile stress obtained, it provides an unexpectedly improved degree of resistance to quasi-static and dynamic impacts.

In some embodiments of the display module 100a shown in FIG. 1A, the first adhesive 10a is about 0.1 to about 0.5, for example about 0.1 to about 0.45, about 0.1 to about 0.4, about 0.1 to about 0.35, about 0.1 to about 0.3, about 0.1 to about 0.25, about 0.1 to about 0.2, about 0.1 to about 0.15, about 0.2 to about 0.45, about 0.2 to about 0.4, about 0.2 to about 0.35, about 0.2 to about 0.3, About 0.2 to about 0.25, about 0.25 to about 0.45, about 0.25 to about 0.4, about 0.25 to about 0.35, about 0.25 to about 0.3, about 0.3 to about 0.45, about 0.3 to about 0.4, about 0.3 to about 0.35, about 0.35 To about 0.45, about 0.35 to about 0.4, and about 0.4 to about 0.45 Poisson's ratio. Other embodiments include a first adhesive characterized by a ratio of Poisson or a ratio of any Poisson between about 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, or these values ( 10a). In some aspects, the ratio of the Poisson of the first adhesive 10a is from about 0.1 to about 0.25.

As outlined above, the display module 100a shown in FIG. 1A includes an adhesive 10a having specific material properties (eg, an elastic modulus of about 0.001 GPa to 10 GPa). In the module (100a) representative of an adhesive which can be used as an adhesive (10a) is optically transparent adhesive ( "OCAs") (for example, Henkel Corporation LOCTITE ^® liquid OCAs), for epoxy, and the stack (90a) (e.g., Other connecting materials understood by those skilled in the art suitable for connecting the substrate 60) to the second major surface 56 of the cover element 50. Other representative adhesives that can be used as the adhesive 10a in the module 100a are epoxy, urethane, acrylate, acrylic, styrene copolymer, polyisobutylene, polyvinyl butyral, ethylene vinyl acetate, sodium silicate, optically clear Adhesives (OCA), pressure sensitive adhesives (PSA), polymeric foams, natural resins, and synthetic resins.

Referring back to FIG. 1A, stack 90a of foldable module 100a includes a substrate comprising components having a glass composition, first and second major surfaces 64, 66, and thickness 62 ( 60). Since it includes components having a glass composition, the substrate 60, in some embodiments, is about 20 GPa to 140 GPa, such as about 20 GPa to about 120 GPa, about 20 GPa to about 100 GPa, about 20 GPa to about 80 GPa, about 20 GPa to about 60 GPa, about 20 GPa to about 40 GPa, about 40 GPa to about 120 GPa, about 40 GPa to about 100 GPa, about 40 GPa to about 80 GPa, about 40 GPa To about 60 GPa, about 60 GPa to about 120 GPa, about 60 GPa to about 100 GPa, about 60 GPa to about 80 GPa, about 80 GPa to about 120 GPa, about 80 GPa to about 100 GPa, and about 100 GPa to It may have an elastic modulus of about 120 GPa. The substrate 60 can be a component having a glass composition or can include at least one component having a glass composition. In the latter case, the substrate 60 can include one or more layers comprising a glass-containing material, for example, the substrate 60 is a polymer/glass composite composed of second phase glass particles in a polymer matrix. Can be In some aspects, the substrate is a glass element characterized by an elastic modulus of about 50 GPa to about 100 GPa, or any modulus value or range of values between these limits. In other aspects, the modulus of elasticity of the substrate 60 is about 20 GPa, 30 GPa, 40 GPa, 50 GPa, 60 GPa, 70 GPa, 80 GPa, 90 GPa, 100 GPa, 110 GPa, 120 GPa, 130 GPa, 140 GPa, or any modulus value or range of values between these values. Moreover, in some embodiments, the substrate 60 is substantially similar or identical to the cover element 50 in terms of the glass composition.

In the specific example of the display module 100a shown in FIG. 1A, the substrate 60 may be about 100 μm to about 1500 μm, for example, about 100 μm to about 1250 μm, about 100 μm to about 1000 μm, about 100 μm to about 750 μm, about 100 μm to about 500 μm, about 100 μm to about 400 μm, about 100 μm to about 300 μm, about 100 μm to about 200 μm, 500 μm to about 1500 μm, for example About 500 μm to about 1250 μm, about 500 μm to about 1000 μm, about 500 μm to about 750 μm, about 750 μm to about 1500 μm, about 750 μm to about 1250 μm, about 750 μm to about 1000 μm, about 1000 A thickness 62 in the range of μm to about 1500 μm, about 1000 μm to about 1250 μm, or any thickness or thickness between these thickness values. Moreover, given the thickness 62 of the substrate 60, the display module 100a is, to some extent, bent or bent at a bending radius of, for example, about 10 mm or more, or 5 mm or more, in certain embodiments. It can be built or mechanically deformed.

In some implementations, a suitable material that can be used as the substrate 60 in the module 100a mounts the electronic device 102 and has high mechanical integrity and flexibility when subjected to bending associated with the foldable electronic device module 100a. Suitable for retention include various thermoset and thermoplastic materials, such as polyimide. For example, the substrate 60 can be an organic light emitting diode (“OLED”) display panel. The material selected for the substrate 60 may also exhibit high thermal stability to resist material property changes and/or degradation associated with the application environment of the module 100a and/or its processing conditions.

The stack 90a of the display module 100a shown in FIG. 1A may also include one or more electronic devices (not shown) connected to the substrate 60. These electronic devices can be conventional electronic devices used in conventional OLED-containing display devices. For example, the substrate 60 of the stack 90a, along with one or more electronic devices in the form and structure of touch sensors, polarizers, and the like, and other electronic devices, is an adhesive or other for connecting these devices to the substrate. Compounds. Moreover, the electronic device can be located within the substrate 60 and/or on one or more of its major surfaces 64, 66.

As also shown in FIG. 1B, the display module 100b has (c) a thickness 72 of about 25 μm to about 200 μm, and an interlayer elastic modulus of about 20 GPa to about 140 GPa, with a glass composition An intermediate layer 70 further comprising urea; And (d) connecting the intermediate layer 70 to the substrate 60, and comprising an elastic modulus of about 0.001 GPa to about 10 GPa and a thickness 12b of about 5 μm to about 50 μm (12b). It is represented in a representative form as a 5-layer module having a stack 90a further comprising (ie, in addition to the first adhesive 10a and the substrate 60). Unless otherwise stated, the intermediate layer 70 may be composed of the same or similar composition, thickness and modulus of elasticity as the cover element 50. Moreover, unless stated otherwise, the second adhesive 10b may be composed of the same or similar composition, thickness and modulus of elasticity as that of the first adhesive 10a. More generally, the configuration of the display modules 100a, 100b shows that display modules having any number of layers can be used in accordance with the principles of the present disclosure.

Hereinafter, referring to FIG. 2, the pen drop test apparatus 200 is illustrated. "Pen drop test", as used herein, is performed with the pen drop device 200 to characterize the stress states observed at the major surfaces 54, 56 of the cover element, display modules 100a, 100b ) (FIGS. 1A and 1B, see) Impact resistance was evaluated. As described and mentioned herein, the pen drop test is a method in which the load of the display module 100a, 100b is transferred to the exposed surface of the cover element 50, i.e., the main surface 54 (i.e., fixed at 25 cm). It is a dynamic test that is performed as being tested with a load from a pen dropping at height. The opposite side of the display module 100a, 100b, e.g., the main surface 66 (see FIGS. 1A and 1B, see FIG. 1 ), is 6063, as polished to an aluminum plate (surface roughness using 400 grit paper). Aluminum alloy). One tube is used according to the pen drop test to guide the pen to the sample, and the tube is placed in contact with the top surface of the sample such that the longitudinal axis of the tube is substantially perpendicular to the top surface of the sample. Each tube has an outer diameter of 2.54 cm (1 inch), an inner diameter of 1.4 cm (9/16 inch), and a length of 90 cm. Acrylonitrile butadiene ("ABS") shims are used to hold the pen at a desired height of 25 cm (height of the ball on the substrate surface) for each test. After each drop, the tube is repositioned relative to the sample to direct the pen to a different impact location on the sample. The pen used in the pen drop test had a weight of 5.7 grams, including a ball point tip 212 and cap with a diameter of 0.35 mm. According to the pen drop test shown in FIG. 2, with the cap attached to the top (i.e. the opposite end of the tip), the ball point 212 can interact with the test sample, i.e., the display modules 100a, 100b. The pen falls.

Advantageously, the pen drop test, as performed with the pen drop test apparatus shown in FIG. 2, occurs at the major surfaces 54, 56 of the cover element 50 based on a fixed pen drop height of 25 cm. It is modeled using FEA technique to estimate the tensile stress. As further understood by those skilled in the art of the present disclosure, certain assumptions are made in performing this modeling, in particular, the cover element 50 and the substrate 60 have a modulus of elasticity of 71 GPa and a Poisson of 0.22. It is assumed to have a rain. Moreover, it is assumed that conventional optical adhesives exhibit an elastic modulus of 0.3 GPa and a Poisson's ratio of 0.49 for the first and second adhesives. Further in connection with pen drop test modeling, the following additional assumptions are made: pen tip 212 is modeled as a rigid body without pen tip deformation; A quarter symmetric slice of module 100a is used; All interfaces in module 100a are assumed to be perfectly coupled during analysis, without delamination; The aluminum support plate mentioned in connection with the pen drop test apparatus 200 is modeled as a rigid aluminum plate; A frictionless contact between the module 100a and the aluminum support plate is assumed; It is assumed that the pen tip 212 does not penetrate the cover element 50 of the module 100a; Use linear-elastic or super-elastic material properties for the elements of module 100a; Using a large variant approach; And during the simulated test, module 100a is at room temperature.

In a specific implementation of the display modules 100a, 100b (see FIGS. 1 a and 1 b, see), the module, upon modeling a pen drop height of 25 cm (see FIG. 2 ), upon impact to the cover element in a pen drop test. , Impact resistance characterized by a tensile stress of less than about 4000 MPa on the first major surface 54 of the cover element 50 and a tensile stress of less than about 12000 MPa on the second major surface 56 of the cover element 50 Can represent Unexpectedly, as understood through this modeling of the pen drop test, the thickness (12a, 12b) of the adhesive (10a, 10b) and the thickness (52) of the cover element (50), for the cover element in the pen drop test, Module 100a such that upon impact, the tensile stress at the first major surface 54 of the cover element 50 is less than about 4000 MPa and the tensile stress at the second major surface 56 of the cover element 50 is less than about 9000 MPa. ) Can be adjusted to further improve the impact resistance. The perspectives of the display module 100a are also compared to the thickness of a conventional adhesive used in such electronic device applications, the first adhesive to a relatively thinner thickness 12a, for example from about 5 μm to about 25 μm. It may include (10a). Similarly, the display module 100a may also have a relatively thinner thickness 52, for example from about 75 μm to about 150, compared to the thickness of other glass-containing cover elements used in such electronic device applications. The cover element 50 can be comprised from about 50 μm to about 150 μm. By this modeling and design of the first adhesive 10a and the cover element 50, the tensile stress at the first major surface 54 of the cover element 50 is less than about 4000 MPa, 3900 MPa, 3800 MPa, 3700 MPa, 3600 MPa, 3500 MPa, 3400 MPa, 3300 MPa, 3200 MPa, 3100 MPa, 3000 MPa or less. Similarly, the tensile stress at the second major surface 56 of the cover element 50 is less than about 12000 MPa, 11000 MPa, 10000 MPa, 9000 MPa, 8000 MPa, 7500 MPa, 7000 MPa, 6500 MPa, 6000 MPa, It can be reduced to 5500 MPa, 5000 MPa, 4500 MPa, 4000 MPa, 3500 MPa, or 3000 MPa or less.

Referring again to FIG. 2, the pen drop test apparatus 200 is shown. As used herein, “semi-static indentation test” is characterized by the stress states observed at the major surfaces 54, 56 of the cover element, display modules 100a, 100b (see FIGS. 1A and 1B). It is performed with a pen dropping device 200 to evaluate the impact resistance. The quasi-static indentation test, as described and mentioned herein, is tested with a constant load of 60 N passed to the exposed surface of the cover element 50, ie the main surface 54, of the display module 100a, 100b sample. It is a quasi-static test performed as much as possible. The opposing faces of the display modules 100a, 100b, e.g., the main surface 66 (see FIGS. 1A and 1B,) are attached to an aluminum plate (6063 aluminum alloy, polished to a surface roughness using 400 grit paper). Is supported by. The pen used for the quasi-static indentation test weighed 5.7 grams, including a ball point tip 212 and cap, 0.5 mm in diameter. According to the quasi-static indentation test shown in FIG. 2, the pen is applied directly to the exposed surface of the cover element 50 with a constant load of 60 N or with a continuously higher load starting at 5 N and breaking up.

Advantageously, the quasi-static indentation test, as performed with the pen drop test apparatus shown in FIG. 2, is the tensile generated at the major surfaces 54, 56 of the cover element 50 based on the applied load of 60N. It is modeled using FEA technology to evaluate stress. As further understood by those skilled in the art in the field of the present disclosure, certain assumptions are made in performing this modeling. In particular, it is assumed that the cover element 50 and the substrate 60 have an elastic modulus of 71 GPa and a Poisson's ratio of 0.22. Moreover, it is assumed that the conventional optical adhesive exhibits an elastic modulus of 0.3 GPa and a Poisson's ratio of 0.49 for the first and second adhesives. In further regard to quasi-static test modeling, the following additional assumptions are made: The pen tip 212 is modeled as a rigid body without pen tip deformation; 1/4 symmetrical slices of modules 100a, 100b are used; All interfaces in modules 100a, 100b are assumed to be fully coupled during analysis, without delamination; The aluminum support plate mentioned in connection with the pen drop test apparatus 200 is modeled as a rigid aluminum plate; Friction-free contact between the modules 100a, 100b and the aluminum support plate is assumed; It is assumed that the pen tip 212 does not penetrate the cover elements 50 of the modules 100a, 100b; Use linear-elastic or super-elastic material properties for the elements of modules 100a, 100b; Using a large variant approach; And during the simulated test the modules 100a, 100b are at room temperature.

In certain implementations of the display module 100a, 100b (see FIGS. 1A and 1B, see FIG. 1 ), the module is modeled with a fixed load of 60 N (see FIG. 2 ), which covers upon impact to the cover element in a semi-static indentation test. It can exhibit impact resistance characterized by a tensile stress of less than about 4700 MPa at the second major surface 56 of the element. Unexpectedly, as understood through this modeling of the quasi-static indentation test, the thicknesses 12a, 12b of the adhesives 10a, 10b and the thickness 52 of the cover element 50 are in the semi-static indentation test. It can be adjusted to further improve the impact resistance of the modules 100a, 100b such that the tensile stress at the second major surface 56 of the cover element 50 upon impact to the cover element is less than about 3200 MPa. The perspectives of the display module 100a are also compared to the thickness of a conventional adhesive used in such electronic device applications, the first adhesive to a relatively thinner thickness 12a, for example from about 5 μm to about 25 μm. It may include (10a). Similarly, the display module 100a may also have a relatively thinner thickness 52, for example from about 75 μm to about 150, compared to the thickness of other glass-containing cover elements used in such electronic device applications. The cover element 50 can be comprised from about 50 μm to about 150 μm. By this modeling and design of the first adhesive 10a and cover element 50, the tensile stress at the second major surface 56 of the cover element 50 is less than about 4700 MPa, 4600 MPa, 4500 MPa, 4400 MPa, 4300 MPa, 4200 MPa, 4100 MPa, 4000 MPa, 3900 MPa, 3800 MPa, 3700 MPa, 3600 MPa, 3500 MPa, 3400 MPa, 3300 MPa, 3200 MPa, 3100 MPa, 3000 MPa or less.

Referring still to FIGS. 1A and 1B, the cover element 50 of the display module 100a, 100b may, from certain aspects of the present disclosure, cover elements from the first and/or second major surface 54, 56 ( 50) may include a glass layer or component having one or more compressive stress regions (not shown) extending to a selected depth. Moreover, from a particular point of view of the modules 100a, 100b, edge compressive stress regions extending from the edges of the element 50 (eg, perpendicular or substantially perpendicular to the major surfaces 54, 56) to a selected depth. (Not shown) may also occur. For example, the compressive stress region or regions (and/or edge compressive stress regions) contained in the glass cover element 50 can be formed by an ion-exchange (“IOX”) process. As another embodiment, the glass cover element 50 can be used to generate one or more of these compressive stress regions through mismatches in the coefficient of thermal expansion (“CTE”) associated with the layers and/or regions. And/or regions.

In view of these aspects of the display module 100a, 100b with a cover element 50 having one or more compressive stress regions formed by an IOX process, the compressive stress region(s) comprises a plurality of ion-exchangeable metal ions and multiple Ion-exchange metal ions of the ion-exchange metal ions are selected to generate compressive stress in the compressive stress region(s). In some aspects of module 100a containing compressive stress region(s), the ion-exchanged metal ion has an atomic radius greater than the atomic radius of the ion-exchangeable metal ion. Ion-exchangeable ions (eg, Na ⁺ ions) are present in the glass cover element 50 before being applied to the ion exchange process. Ion-exchange ions (e.g., K ⁺ ions) are part of the ion-exchangeable ions within the region(s) within the element 50 that are incorporated into the glass cover element 50 and ultimately become compressive stress region(s) Can replace The incorporation of ion-exchange ions, e.g., K ⁺ ions, into the cover element 50 is performed in a molten salt bath (e.g., molten KNO ₃ salt) containing ion-exchange ions (e.g. This can be accomplished by immersing the element 50) prior to formation of the module 100a. In this embodiment, the K ⁺ ions have a larger atomic radius than the Na ⁺ ions, and tend to generate local compressive stress in the glass cover element 50, for example, wherever present in the compressive stress region(s). have.

Depending on the ion-exchange process conditions used for the cover elements 50 used in the display modules 100a, 100b shown in FIGS. 1A and 1B, the ion-exchange ions are the first major component of the cover element 50. It can be passed from surface 54 to a first ion exchange depth (not shown, “DOL”) to establish the depth of ion exchange compression (“DOC”). DOC, as used herein, refers to the depth at which stress changes from compression to tensile in the chemically strengthened alkali aluminosilicate glass article described herein. DOC relies on ion exchange treatment to a surface stressometer (a commercially available instrument, such as FSM-6000, manufactured by FSM-Orihara Industrial Co., Ltd. (Japan)) or a scattered polarizing polarizer (SCALP). It can be measured by. When stress is generated in the glass article by exchanging potassium ions into the glass article, FSM is used to measure the DOC. When stress is generated by exchanging sodium ions into a glass article, SCALP is used to measure DOC. When stress is generated in the glass article by exchanging both potassium and sodium ions into the glass, DOC is measured by SCALP, where the exchange depth of sodium represents DOC, and the exchange depth of potassium ions changes in the magnitude of compressive stress ( However, it is believed that the stress does not change from compression to tension); The depth of exchange of potassium ions in these glass articles is measured by FSM. Compressive stress (including surface CS) is measured by FSM. Surface stress measurement relies on accurate measurement of the stress optical coefficient (SOC) associated with birefringence of glass. SOC is eventually measured according to the procedure C (Glass Disc Method) described in ASTM standard C770-16, the name of which is "Standard Test Method for Measurement of Glass Stress-Optical Coefficient", the entire contents of which are incorporated herein by reference. do. Similarly, a second zone of compressive stress can occur in the element 50 from the second major surface 56 to the second ion exchange depth. Compressive stress levels far exceeding 100 MPa in DOL can be achieved up to 2000 MPa with this IOX process. The compressive stress level in the compressive stress region(s) in the cover element 50 may serve to counteract the tensile stress generated in the cover element 50 upon bending of the foldable electronic device module 100a.

Referring again to Figures 1A and 1B, display modules 100a and 100b, in some implementations, cover at edges perpendicular to first and second major surfaces 54 and 56, respectively, defined by compressive stress of 100 MPa or more, respectively. Element 50 may include one or more edge compressive stress regions. It should be understood that these edge compressive stress regions may occur at any one of its edge or surfaces separate from its main surface in the cover element 50, depending on the shape or shape of the element 50. For example, in some implementations of display module 100a, 100b with elliptic-shaped cover element 50, the edge compressive stress regions are the outer edge of the element that is perpendicular (or substantially vertical) from the main surfaces of the element. Can be generated inwards. An IOX process substantially similar to that used to generate the compressive stress region(s) close to the major surfaces 54, 56 can be deployed to create these edge compressive stress regions. More specifically, any such edge compressive stress regions in the cover element 50 are, for example, non-uniform bending of the cover element 50 and/or its edges at its major surface 54, 56. It can be used to counteract the tensile stress generated at the edge of the element through quasi-static or dynamic impact on the cover element 50 (and modules 100a, 100b) across either. Optionally, or in addition, without being bound by theory, any such edge compressive stress regions used in the cover element 50 may have an impact or wear event on the element 50 or on the edge within the modules 100a, 100b. Can counteract adverse effects from

Referring back to FIGS. 1A and 1B, from the perspectives of display module 100a, 100b with cover element 50 having one or more compressive stress regions formed through mismatch of CTEs of regions or layers within element 50. , These compressive stress regions are created to match the structure of element 50. For example, a CTE difference in element 50 can create one or more areas of compressive stress within the element. In one embodiment, the cover element 50 may include a core region or layer sandwiched by clad regions or layers, each substantially parallel to the main surface 54, 56 of the element. Moreover, the core layer is adjusted to a CTE greater than the CTE of the clad regions or layers (eg, by compositional control of the core and clad layer or region). After the cover element 50 has cooled from its manufacturing process, the CTE difference between the core region or layer and the clad regions or layers causes uneven volumetric contraction upon cooling, predominantly within the clad regions or layers. The occurrence of residual stresses in the cover element 50 which appeared in the occurrence of compressive stress regions under the surfaces 54, 56. In other words, the core region or layer and clad regions or layers are in close contact with each other at high temperature; These layers or regions are then cold so that a large volume change in the high CTE core region (or layer) compared to the low CTE clad regions (or layers) creates compressive stress regions in the clad regions or layers within the cover element 50. Is cooled.

Referring still to the cover elements 50 of the modules 100a, 100b, shown in FIGS. 1A and 1B with CTE-generated compressive stress regions, the CTE-related compressive stress regions, respectively, are the first major surface 54 From to the first CTE region depth, from the second major surface 56 to the second CTE region depth, and thus within the clad layer or regions and to each of the compressive stress regions associated with each major surface 54, 56. CTE-related DOLs are established. In some aspects, the compressive stress level in these compressive stress regions may exceed 150 MPa. Maximizing the difference in CTE value between the core region (or layer) and the clad region (or layer) can increase the magnitude of the compressive stress generated in the compressive stress regions upon cooling of the element 50 after manufacture. In certain implementations of display modules 100a, 100b with cover elements 50 having such CTE-related compressive stress regions, the cover elements 50 have a thickness of 3 or more divided by the sum of the clad region thicknesses divided by the core region thickness. The core area and the clad area are used as the ratio. Thus, maximizing the size of the clad region and/or the core region compared to the CTE and/or its CTE serves to increase the magnitude of the compressive stress level observed in the compressive stress regions of the display module 100a, 100b. can do.

Among other advantages, compressive stress regions (eg, as generated through an IOX- or CTE-related approach outlined in the preceding paragraph), display modules 100a, 100b (FIGS. 1A and 1B, Cover element (50) to compensate for the tensile stress reaching the maximum at one of the major surfaces (54, 56), depending on the nature of the impact, in particular the nature of the impact upon the element upon quasi-static or dynamic impact. ). In certain aspects, the compressive stress region can include a compressive stress of at least about 100 MPa at the major surfaces 54, 56 of the cover element 50. In some aspects, the compressive stress at the main surface is between about 600 MPa and about 1000 MPa. In other respects, the compressive stress can exceed 1000 MPa at the main surface, up to 2000 MPa, depending on the process used to create compressive stress in the cover element 50. Compressive stress can also range from about 100 MPa to about 600 MPa at the major surface of element 50 in other aspects of the present disclosure. In an additional aspect, the compressive stress region (or regions) within the cover element 50 of the modules 100a, 100b is about 100 MPa to about 2000 MPa, for example about 100 MPa to about 1500 MPa, about 100 MPa to about 1000 MPa, about 100 MPa to about 800 MPa, about 100 MPa to about 600 MPa, about 100 MPa to about 400 MPa, about 100 MPa to about 200 MPa, about 200 MPa to about 1500 MPa, about 200 MPa to About 1000 MPa, about 200 MPa to about 800 MPa, about 200 MPa to about 600 MPa, about 200 MPa to about 400 MPa, about 400 MPa to about 1500 MPa, about 400 MPa to about 1000 MPa, about 400 MPa to about 800 MPa, about 400 MPa to about 600 MPa, about 600 MPa to about 1500 MPa, about 600 MPa to about 1000 MPa, about 600 MPa to about 800 MPa, about 800 MPa to about 1500 MPa, about 800 MPa to about 1000 MPa, And about 1000 MPa to about 1500 MPa.

Within this compressive stress region used in the cover element 50 of the display modules 100a, 100b (see FIGS. 1A and 1B, see), the compressive stress is constant as a function of depth from the main surface to one or more selected depths. It can be maintained, reduced or increased. As such, various compressive stress profiles can be used in the compressive stress region. Moreover, the depth of each compressive stress region can be set to approximately 15 μm or less from the major surfaces 54 and 56 of the cover element 50. In other aspects, the depth of the compressive stress region(s) is approximately one third or less of the thickness 52 of the cover element 50 from the first and/or second major surfaces 54, 56, or It can be set to approximately 20% or less of the thickness 52 of the element 50.

Referring again to FIGS. 1A and 1B, the display modules 100a and 100b are glass materials having one or more compressive stress areas having a maximum blemish size of 5 μm or less at the first and/or second major surfaces 54 and 56 It may include a cover element 50 comprising a. The maximum flaw size may also be maintained in a range of about 2.5 μm or less, 2 μm or less, 1.5 μm or less, 0.5 μm or less, 0.4 μm or less, or even a smaller flaw size. The reduction of the blemish size in the compressive stress region of the glass cover element 50 is due to crack propagation upon application of tensile stress by impact-related forces to the display modules 100a, 100b (see FIGS. 1a, 1b and 2,). The tendency to break the element 50 can be further reduced. Additionally, some aspects of the modules 100a, 100b may have a controlled defect size distribution (eg, 0.5 μm at the first and/or second major surface 54, 56) without the use of one or more compressive stress regions. Surface area having the following defect size).

Referring again to FIGS. 1A and 1B, other implementations of the display modules 100a, 100b allow the glass material to be applied to various etching processes adjusted to improve defect distribution within the element 50 and/or reduce defect size. It may include a cover element 50 comprising. This etch process can be used to control the defect distribution within the cover element 50 near its main surface 54, 56 and/or along its edges (not shown). For example, to weakly etch the surface of the cover element 50 with the glass composition, an etching solution containing about 15% by volume HF and 15% by volume HCl can be used. The time and temperature of light etching can be set, as will be understood by those skilled in the art, depending on the level of material removal from the surface of the cover element 50 and the composition of the element 50. Some surfaces of element 50 may remain unetched using a masking layer or the like on these surfaces during the etching procedure. More specifically, such light etching can advantageously improve the strength of the cover element 50. In particular, cutting or singulating processes used to partition glass structures ultimately used as cover elements 50 may leave blemishes and other defects within the surface of the element 50. These blemishes and defects can propagate during the application of stress to the modules 100a, 100b containing the element 50 from the application environment and use, and can cause glass breakage. The selective etching process can increase the strength and/or fracture resistance of the slightly-etched surface by slightly etching one or more edges of element 50 to remove at least some of the flaws and defects. Additionally or alternatively, a photo etch step can be performed after chemical tempering (eg, ion exchange) of cover element 50. This chemical etching after chemical tempering can reduce any blemishes introduced by the chemical tempering process itself, thus increasing the strength and/or fracture resistance of the cover element.

In addition, the cover element 50 used in the display modules 100a, 100b shown in FIGS. 1A and 1B includes the aforementioned strength-enhancing features: (a) IOX-related compressive stress regions. ; (b) CTE-related compressive stress regions; And (c) an etched surface with a smaller defect size; It should be understood that it may include any one or more of. These strength-enhancing features can be used to offset or partially offset the tensile stress generated at the surface of the cover element 50 related to the application environment, use and processing of the display modules 100a, 100b.

In some implementations, the display modules 100a, 100b shown in FIGS. 1A and 1B can be used in displays, printed circuit boards, housings, or other features related to the final product electronic device. For example, display modules 100a, 100b can be used in electronic display devices containing numerous thin film transistors (“TFTs”) or LCD or OLED devices containing low-on polysilicon (“LTPS”) backplanes. . When the display modules 100a, 100b are used in a display, for example, the modules 100a, 100b may be substantially transparent. Moreover, the modules 100a, 100b can have desirable impact resistance with respect to quasi-static and dynamic impacts, as described in the preceding paragraph. In some implementations, the display modules 100a, 100b are used in wearable electronic devices, such as watches, wallets, or bracelets. “Foldable”, as defined herein, includes full folding, partial folding, bending, bending, discontinuous bending, and multi-folding performance; Moreover, even if the display is outside of the device when folded or inside the device when folded, the device can be folded.

Example

In this embodiment, a comparative display module (B.S. 1) and a display module (eg, S. 1-1 to 1-4, 2-1 and 2-2) consistent with aspects of the present disclosure are , Simulated quasi-static and dynamic impact according to each quasi-static indentation test and pen drop test. Additionally, an actual quasi-static indentation test was performed to obtain peak load versus failure values for some of the samples, looking for changes in the actual indentation load up to failure. The results of these modeling and experimental measurements are shown in Figures 3A-7. Moreover, the legend in these charts describes the configuration of the modeled and/or tested display modules. For example, B.S. 1 is composed of a glass cover element having a thickness of 100 μm, a first adhesive comprising a PSA material having a thickness of 100 μm, and a substrate containing a glass 1 composition having a thickness of 1.1 mm. Although the substrate was modeled with a thickness of 1.1 mm, this was done to show the effect of the adhesive layer on the stack. The substrate need not have a thickness of 1.1 mm; Instead, as mentioned elsewhere, the substrate may have a thickness of less than 1.1 mm, for example, as described above with respect to the substrate 62, and the trend is still on a 1.1 mm thick glass substrate. It will be similar to that observed.

Referring to FIG. 3A, a plot of the load applied to the module in the modeled quasi-static indentation test versus the maximum principal stress at the second major surface of the cover element of the display module is a peak of 60N, according to some aspects of the present disclosure. Loads are provided. As is apparent from the figure, 3 with a first adhesive having a smaller thickness of about 15 μm to about 50 μm, compared to a module having a greater first adhesive thickness of about 100 μm (B. S. 1) -The layer display module (sil. 1-1 to 1-4) shows the lowest maximum principal stress level at the second major surface of the cover element. Moreover, the three-layer display modules (sil. 1-1 to 1-4) have lower maximum principal stresses on the second major surface of the cover element compared to the five-layer display modules (sil. 2-1 and 2-2). Shows the level Additionally, a display module with a slightly thicker cover element (sil. 1-4, cover element thickness = 130 μm), a similarly configured display module with a slightly thinner cover element (sil. 1-2, cover element thickness) = 100 μm), showing a lower maximum principal stress level at the second major surface of the cover element.

Without being bound by theory, taking into account the results shown in FIG. 3A, a relatively softer first adhesive material comprising a pressure sensitive adhesive (PSA) material facilitates localized bending of the display glass under the puncture tip of the testing device. To do. Small radius tips (see FIG. 2, radius = 0.5 mm) tend to result in highly localized bending that creates high tensile stress on the major surface of the cover element. As the bending stress is related to the overall stiffness of the module, it is pushed that increasing the stiffness of the module can lead to improved impact performance.

Referring now to FIG. 3B, a plot of load versus strain for a display module applied to a modeled quasi-static indentation test is provided up to a peak load of 60 N, previously used to generate the results of FIG. 3A. . Moreover, the slope of the load versus strain curve in FIG. 3B is a measure of the stiffness of the display module. Considering the results shown above in FIG. 3A, it is clear that, as shown in FIG. 3B, modules with higher stiffness values tend to perform better in terms of reduced maximum principal stress at the second major surface of the cover element. Do. In other words, the maximum tensile stress at the second major surface of the cover element observed from the quasi-static indentation test is inversely proportional to the stiffness of the module.

Referring now to FIG. 4, a plot of experimentally-determined peak failure loads for some of the modules modeled in the quasi-static indentation test and schematically shown in FIGS. 3A and 3B is provided. In particular, two three-layer modules (rooms 1-2 and 1-3) and two five-layer modules (rooms 2-1 and 2-2) are increasing to generate an average load for breakage. The applied load (not a constant load of 60 N) is applied to the actual semi-static indentation test. Microscopic analysis performed on these samples (Fractography analyses), all turned out to have experienced a biaxial failure mechanism. Moreover, as is evident from the results shown in FIG. 4, the three-layer display module exhibits a significantly higher peak load for breakage than the five-layer display module. These results, given the relatively small amount of adhesive present in these designs (i.e., one adhesive for a three-layer module and two adhesives for a five-layer module), allow the three-layer display modules to It is believed to be due to the fact that it is more robust than its 5-layer counterpart module.

Referring now to FIGS. 5A and 5B, modeled in a pen drop test with a pen drop height of 25 cm, the distance from the impact position versus the respective cover elements of each display element of the same group of display modules shown in FIGS. 3A and 3B. Plots of maximum principal stresses on the second major surface and the first major surface are provided. As generally evident from Figures 5A and 5B, the tensile stress at the second major surface of the cover element is significantly greater than the tensile stress observed at the first major surface for the same pen drop height of 25 cm. Without being bound by theory, the higher tensile stress observed at the second major surface of the cover element is due to the localized bi-axial bending of the cover element, and the somewhat lower tensile stress at the first major surface is the pen drop. The test is pushed to be related to Hertzian contact with the pen tip (see FIG. 2,).

Referring again to Figures 5A and 5B, the spatial variation of tensile stress at the second and first major surfaces of the cover element is shown, as resulted from the pen drop test simulated with a 25 cm pen drop height. . In particular, display modules having a thinner first adhesive thickness level (e.g., yarns 1-1 to 1-3, thicknesses of about 15-50 μm) can be used for display modules having a larger first adhesive thickness (i.e. , B. sil. 1, thickness = 100 μm) experience lower tensile stress on all major surfaces. Moreover, the three-layer display modules (s. 1-1 to 1-4), as result from the pen drop test, cover elements compared to the five-layer display modules (s. 2-1 and 2-2). Shows a lower maximum principal stress level on all of the main surfaces. Additionally, a display module with a slightly thicker cover element (sil. 1-4, cover element thickness = 130 μm), a similarly configured display module with a slightly thinner cover element (sil. 1-2, cover element thickness) = 100 μm), showing a lower maximum principal stress level on all major surfaces of the cover element.

Referring now to Figures 6A and 6B, the second major of the cover elements for the display module of the same group shown in Figures 3A and 3B versus time from impact as modeled in a pen drop test with a pen drop height of 25 cm. On the surface, plots for maximum principal stress and strain, respectively, are provided. In particular, FIGS. 6A and 6B show that when the display module experiences its maximum deformation associated with pen drop at 25 cm, the maximum tensile stress observed at the second major surface occurs. Thus, the maximum tensile stress observed at the second major surface of the cover element is a function of the overall stiffness of the display module.

Referring now to FIG. 7, at the second major surface of the cover element of the display module of the same group shown in FIGS. 3A-3B, with a percentage increase in each of these stress values relative to the lowest maximum principal stress observed in the sample. A bar chart of maximum principal stress is provided. That is, the seal, which is a display module with the highest performance (ie, the lowest observed main stress at the second major surface of the cover element, ˜7700 MPa). 1-1 serves as a standard for this chart. In particular, display modules with adhesives comprising PSA and a thickness of 15 μm show the best performance. The chart of FIG. 7 further shows that an increase in the thickness of the adhesive (eg, B. 1, thickness ~100 μm) results in an increase in tensile stress of about 59% over the reference condition. The chart of FIG. 7 also shows that the three-layer display modules (sil. 1-1 to 1-4) are at the second major surface of the cover element compared to the five-layer display modules (sil. 2-1 and 2-2). It further shows that it shows a lower maximum principal stress level.

It will be apparent to those skilled in the art that various changes and changes can be made to the foldable electronic device module of the present disclosure without departing from the spirit or scope of the claims.

Claims (15)

A cover element having a thickness of about 25 μm to about 200 μm and a cover element elastic modulus of about 20 GPa to about 140 GPa, further comprising components having a glass composition, a first major surface, and a second major surface; And
A display module comprising a stack,
The stack is:
(a) a substrate comprising a component having a thickness of about 100 μm to 1500 μm and a glass composition, and
(b) connecting the stack to a second major surface of the cover element, the first adhesive comprising a modulus of elasticity of about 0.001 GPa to about 10 GPa and a thickness of about 5 μm to 50 μm,
Here, the display module:
Impact resistance characterized by a tensile stress of less than about 4700 MPa at the second major surface of the cover element upon impact to the cover element in a semi-static indentation test; or
One of the impact resistances characterized by a tensile stress of less than about 4000 MPa on the first major surface of the cover element and a tensile stress of less than about 12000 MPa on the second major surface of the cover element upon impact to the cover element in a pen drop test. The display module including the above. The method according to claim 1,
Wherein the display module comprises impact resistance characterized by a tensile stress of less than about 3200 MPa at the second major surface of the cover element upon impact to the cover element in a semi-static indentation test. The method according to claim 2,
The first adhesive further comprises a thickness of about 5 μm to about 25 μm, and the cover element further comprises a thickness of about 50 μm to about 150 μm. The method according to any one of claims 1-3,
The first adhesive is epoxy, urethane, acrylate, acrylic, styrene copolymer, polyisobutylene, polyvinyl butyral, ethylene vinyl acetate, sodium silicate, optically clear adhesive (OCA), pressure sensitive adhesive (PSA), polymer A display module comprising one or more of a foam, natural resin, or synthetic resin. The method according to any one of claims 1-4,
The stack is:
(c) an intermediate layer having a thickness of about 25 μm to about 200 μm and an interlayer elastic modulus of about 20 GPa to about 140 GPa, further comprising components having a glass composition; And
(d) a display module further comprising a second adhesive connecting the intermediate layer to the substrate and comprising a modulus of elasticity of about 0.001 GPa to about 10 GPa and a thickness of about 5 μm to about 50 μm. The method according to claim 5,
Wherein the display module comprises impact resistance characterized by a tensile stress of less than about 4200 MPa at the second major surface of the cover element upon impact to the cover element in a semi-static indentation test. The method according to claim 6,
Each of the first and second adhesives further includes a thickness of about 5 μm to about 25 μm, and each of the cover element and the intermediate layer further includes a thickness of about 75 μm to about 150 μm. The method according to any one of claims 5-7,
Each of the first and second adhesives includes epoxy, urethane, acrylate, acrylic, styrene copolymer, polyisobutylene, polyvinyl butyral, ethylene vinyl acetate, sodium silicate, optically clear adhesive (OCA), and pressure sensitive adhesive ( PSA), a polymer foam, a natural resin, or a synthetic resin. The method according to any one of claims 5-8,
The display module features a tensile stress of less than about 4000 MPa on the first major surface of the cover element and a tensile stress of less than about 11000 MPa on the second major surface of the cover element upon impact to the cover element in a pen drop test. A display module including impact resistance. The method according to claim 9,
Each of the first and second adhesives further comprises a thickness of about 5 μm to about 25 μm, and each of the cover element and the intermediate layer further comprises a thickness of about 50 μm to about 150 μm. The method according to any one of claims 1-10,
The display module features a tensile stress of less than about 4000 MPa on the first major surface of the cover element and a tensile stress of less than about 9000 MPa on the second major surface of the cover element upon impact to the cover element in a pen drop test. A display module including impact resistance. The method according to any one of claims 1-11,
A display module, measured during a semi-static indentation test, further comprising a stiffness of at least about 750 N/mm. The method according to claim 12,
The display module includes impact resistance characterized by a tensile stress of less than about 3200 MPa at the second major surface of the cover element upon impact to the cover element in a quasi-static indentation test, wherein the display module is quasi-static A display module, measured during an indentation test, comprising a stiffness of at least about 1000 N/mm. The method according to claim 13,
The first adhesive further comprises a thickness of about 5 μm to about 25 μm, and the cover element further comprises a thickness of about 50 μm to about 150 μm. The method according to claim 14,
The first adhesive is epoxy, urethane, acrylate, acrylic, styrene copolymer, polyisobutylene, polyvinyl butyral, ethylene vinyl acetate, sodium silicate, optically clear adhesive (OCA), pressure sensitive adhesive (PSA), polymer A display module comprising one or more of a foam, natural resin, or synthetic resin.

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